如何获知页面上的图象的实际尺寸？

程序员文章站 2022-05-03 13:22:50

下面两个文件： ...

下面两个文件：

<html>
<head>
<title>图像尺寸</title>
</head>
<body bgcolor="#ffffff">
<%
graphic="images/intels.gif"
hw = readimg(graphic)
response.write graphic & " dimensions: " & hw(0) & "x" & hw(1)
& "<br>"
response.write "<img src=""/" & graphic & """"
response.write height=""" & hw(0) & """
response.write width=""" & hw(0) & "">"
%>
</body>
</html>

－－－－－－－－－－－－－－－－－－－－－－－－
graphicdetect.asp
<%
dim hw

function ascat(s, n)
ascat = asc(mid(s, n, 1))
end function

function hexat(s, n)
hexat = hex(ascat(s, n))
end function

function isjpg(fichero)
if instr(ucase(fichero), ".jpg") <> 0 then
isjpg = true
else
isjpg = false
end if
end function

function ispng(fichero)
if instr(ucase(fichero), ".png") <> 0 then
ispng = true
else
ispng = false
end if
end function

function isgif(fichero)
if instr(ucase(fichero), ".gif") <> 0 then
isgif = true
else
isgif = false
end if
end function

function isbmp(fichero)
if instr(ucase(fichero), ".bmp") <> 0 then
isbmp = true
else
isbmp = false
end if
end function

function iswmf(fichero)
if instr(ucase(fichero), ".wmf") <> 0 then
iswmf = true
else
iswmf = false
end if
end function

function iswebimg(f)
if isgif(f) or isjpg(f) or ispng(f) or isbmp(f) or iswmf(f)
then
iswebimg = true
else
iswebimg = true
end if
end function

function readimg(fichero)
if isgif(fichero) then
readimg = readgif(fichero)
else
if isjpg(fichero) then
readimg = readjpg(fichero)
else
if ispng(fichero) then
readimg = readpng(fichero)
else
if isbmp(fichero) then
readimg = readpng(fichero)
else
if iswmf(fichero) then
readimg = readwmf(fichero)
else
readimg = array(0,0)
end if
end if
end if
end if
end if
end function

function readjpg(fichero)
dim fso, ts, s, hw, nbytes
hw = array("","")
set fso = createobject("scripting.filesystemobject")
set ts = fso.opentextfile(server.mappath("/" & fichero), 1)
s = right(ts.read(167), 4)
hw(0) = hextodec(hexat(s,3) & hexat(s,4))
hw(1) = hextodec(hexat(s,1) & hexat(s,2))
ts.close
readjpg = hw
end function

function readpng(fichero)
dim fso, ts, s, hw, nbytes
hw = array("","")
set fso = createobject("scripting.filesystemobject")
set ts = fso.opentextfile(server.mappath("/" & fichero), 1)
s = right(ts.read(24), 8)
hw(0) = hextodec(hexat(s,3) & hexat(s,4))
hw(1) = hextodec(hexat(s,7) & hexat(s,8))
ts.close
readpng = hw
end function

function readgif(fichero)
dim fso, ts, s, hw, nbytes
hw = array("","")
set fso = createobject("scripting.filesystemobject")
set ts = fso.opentextfile(server.mappath("/" & fichero), 1)
s = right(ts.read(10), 4)
hw(0) = hextodec(hexat(s,2) & hexat(s,1))
hw(1) = hextodec(hexat(s,4) & hexat(s,3))
ts.close
readgif = hw
end function

function readwmf(fichero)
dim fso, ts, s, hw, nbytes
hw = array("","")
set fso = createobject("scripting.filesystemobject")
set ts = fso.opentextfile(server.mappath("/" & fichero), 1)
s = right(ts.read(14), 4)
hw(0) = hextodec(hexat(s,2) & hexat(s,1))
hw(1) = hextodec(hexat(s,4) & hexat(s,3))
ts.close
readwmf = hw
end function

function readbmp(fichero)
dim fso, ts, s, hw, nbytes
hw = array("","")
set fso = createobject("scripting.filesystemobject")
set ts = fso.opentextfile(server.mappath("/" & fichero), 1)
s = right(ts.read(24), 8)
hw(0) = hextodec(hexat(s,4) & hexat(s,3))
hw(1) = hextodec(hexat(s,8) & hexat(s,7))
ts.close
readbmp = hw
end function

function isdigit(c)
if instr("0123456789", c) <> 0 then
isdigit = true
else
isdigit = false
end if
end function

function ishex(c)
if instr("0123456789abcdefabcdef", c) <> 0 then
ishex = true
else
ishex = false
end if
end function

function hextodec(cadhex)
dim n, i, ch, decimal
decimal = 0
n = len(cadhex)
for i=1 to n
ch = mid(cadhex, i, 1)
if ishex(ch) then
decimal = decimal * 16
if isdigit(c) then
decimal = decimal + ch
else
decimal = decimal + asc(ucase(ch)) - asc("a")
end if
else
hextodec = -1
end if
next
hextodec = decimal
end function
%>

上一篇：南越王赵佗：历史上寿命最长的皇帝，活了121岁

下一篇：调皮男主角